Automatic reversing jack



Sept. 6, 1960 DE WlTT M. VOLKERT 2,951,679

AUTQMATIC REVERSING JACK 3 Sheets-Sheet 1 Filed Dec. 11, 1958 DE WlTT M.VOLKERT 2,951,679

AUTOMATIC REVERSING JACK Sept. 6, 1960 3 Sheets-Sheet 21 Filed Dec. 11,1958 n KW /W w Sept. 6, 1960 DE WITT M. VOLKERT 2,951,679

AUTOMATIC REVERSING JACK Filed Dec. 11, 1958 I5 Sheets-Sheet 3 UniteSttes Patent AUTOMATIC REVERSING JACK De Witt M. Volkert, Grabill, Ind.

Filed Dec. 11, 1958, Ser. No. 779,685

4 Claims. (Cl. 254-111) This invention relates generally to jacks, suchas the type commonly employed for vehicular use, and more particularlyto an automatic reversing jack construction.

Virtually all commercially available vehicular jacks, particularly ofthe bumper variety, known to the present applicant, have required manualactuation of a reversing lever in order to 'convert from raising tolowering operation. While jack constructions have been proposed in whichreversing is effected automatically, i.e., which do not incorporate amanually actuated reversing lever, to the best of the present applicantsknowledge these constructions have been unduly complex and not suitedfor quantity production. It is therefore desirable to provide anautomatic reversing jack construction which is simpler than priorarrangements and which incorporates a minimum number of readilyassembled parts.

It is therefore an object of my invention to provide an improvedautomatic reversing jack construction.

Another object of my invention is to provide an improved automaticreversing jack construction incorporating a minimum number of readilyassembled parts.

Further objects and advantages of my invention will become apparent byreference to the following description and the accompanying drawings,and the features of novelty which characterize my invention will bepointed out with particularity in the claims annexed to and forming apart of this specification.

My invention, in its broader aspects, provides an automatic reversingjack having an elongated toothed rack bar and a housing having a portionembracing the bar and being relatively slidable thereon. An actuatinglever is provided pivotally mounted on the housing and a holding pawl isprovided also pivotally mounted on the housing and being adapted toengage the teeth of the bar. A lifting pawl is provided pivotallymounted on the actuating lever and also adapted to engage the teeth ofthe bar and spring means urges the two pawls respectively intoengagement with the teeth so that oscillation of the actuating leverbetween first and second intermediate positions alternately causes onepawl to engage a tooth and the other pawl to slide over one tooth and toengage the adjacent tooth, thereby moving the housing in one directionwith respect to the bar. In order to provide automatic reversingoperation, a latching member is provided pivotally mounted on thehousing and having a portion adapted at times to engage the holding pawlthereby to hold the same out of engagement with the teeth of the bar.Means are provided cooperating with the lifting pawl causing the same tomove out of engagement with one tooth and into engagement with anothertooth of the bar responsive to movement of the actuating lever into andaway from one extreme position. The lifting pawl is also adapted to movethe holding pawl into engagement with the latching member responsive tomovement of the lever to the other extreme position and the lifting pawlis further adapted to move the latching member out of engagement withthe holding pawl responsive to movement of the lever away from the otherextreme position so that oscillation of the actuating lever between itsextreme positions moves the housing in the opposite direction withrespect to the bar.

In the drawings, Fig. 1 is a side-elevational view, partly in section,illustrating my improved reversing jack construction in its normalposition;

Fig. 2 is another cross-sectional view illustrating the raising actionof my improved jack construction;

Figs. 3, 4 and 5 are further cross-sectional views illustrating thelowering action of my improved jack construction;

Fig. 6 is a fragmentary end view of my jack construction viewed from theline 66 of Fig. 2; and

Fig. 7 is a fragmentary view in perspective, partly broken away, furtherillustrating. my improved jack construction.

Referring now to the drawings, my improved jack construction, generallyidentified as 20, includes an elongated, stationary, vertical rack bar21 having upwardly'facing rack teeth 22 formed on one side thereof, asshown. A housing member 23 is provided having an end wall 24 and spacedparallel side walls 25 and 26. As best seen in Figs. 6 and 7, side walls25 and 26 are preferably integrally joined by a top wall portion 27;side walls 25 and 26 and top wall 27 may thus conveniently be integrallyformed from suitable sheet steel, the end wall 24 being secured theretoin any suitable manner, as by threaded fastening members 28, as, shown.Rack bar 21 is arranged with its side 29 opposite from teeth 22slidingly engaging the inner surface of the end wall 24 so that teeth 22extend inwardly into the space between the side walls 25 and 26, asshown. A pair of suitable bearing plates 31 and 32 are respectivelyarranged on the inner faces of the side walls 25 and 26 and securedthereto in any suitable manner, as by threaded fasteners 33. The bearingplates 31 and 32 have their forward edges spaced from the end wall 24thus retaining rack bar 21 with teeth 22 extending between the bearingplates 31 and 32, as best seen in Figs. 6 and 7.

The operating mechanism of my improved jack construciton includes anactuating lever 34 having a forked end with its arms 35 and 36 extendinginto the space between side walls 25 and 26 and being pivotally securedthereto by means of a pivot pin 37; hole 38 in side wall 26 whichaccommodates pivot pin 37 is shown in Fig. 7, it being understood that acomparable aligned hole is provided in side wall 25. It will be observedthat bearing plates 31 and 32 respectively have cut-out portions 39 foraccommodating arms 35 and 36 of actuating lever 34. End 41 of actuatinglever 34 extends out of housing 23 and is adapted to have a suitablejack handle 42 positioned thereon for manually oscillating actuatinglever 34 up and down in order to actuate the operating mechanism, aswill be hereinafter more fully described.

An elongated lifting pawl 43 is provided positioned between arms 35 and36 of actuating lever 34 and being pivotally secured thereto by means ofpivot pin 44. Lifting pawl 43 has its lower end 45 arranged to engagethe teeth 22 of rack bar 21. A holding pawl 46 is provided positionedbetween bearing plates 31 and 32 on the side of actuating lever 34remote from the lower end 45 of lifting pawl 43, being pivotally securedbetween bearing plates 31-and 32 by means of a pivot pin 47; pivot pin47 is respectively seated in aligned holes 48'eXtending through therespective side walls and bearing members 25 and 31, and 26 and 32, asshown in Fig. 7. Holding pawl 46 has its lower end 49 adapted to engageteeth 22 of rack bar 21 as shown. A coil spring 51 is provided havingits lower end 52 secured to lower end of lifting pawl 43 and its upperend 53 secured. to "holding pawl 46, spring 51 passing over pivot pin 37of actuating lever 34 as shown; coil spring 51 thus urges lower endsPatented .Sept. ,6, 1960 45 and 49 of lifting and holding pawls 43 and46 into engagement with corresponding teeth 22 of rack bar 21.

Front wall 24 of housing member 23 is provided with a suitable liftingshoulder 54 adapted to engage an automotive bumper and the lower end 55of rack bar 21 is seated in a suitable base member 56, as is well knownin the art. It will now be readily understood that housing 23 togetherwith its lifting shoulder 54 is raised and lowered relative to rack bar21 by suitable action of actuating lever 34 and the operation of thelifting and holding pawls 43 and 46, as will now be described.

The raising action of my improved jack construction will now bedescribed by reference to Figs. 1 and 2. Referring momentarily to Fig.:1, in which the normal position of the operating mechanism is shown, itwill be observed that the lower end.45 of lifting pawl 43 is inengagement with tooth 4 Whereas the lower end 49 of holding pawl 46 isin engagement with tooth 12. Referring now additionally to Fig. 2, itwill be seen that lowering of actuating lever 34 in the direction shownby the. arrow 57 causes lifting pawl 43 to raise the housing 23 in thedirection shown by the arrow 58 from the position shown in dashed lines59 in Fig. 2 to the position shown in solid lines. Raising of thehousing 23 responsive to downward movement of actuating lever 34 causesend 49 of holding pawl 46 to slide upwardly along the bottom side oftooth 13, as shown in solid lines in Fig. 2, and eventually to snap intoand engage tooth 13, as shown in dashed lines 61 in Fig. 2. Return ofthe actuating lever 34 to its normal position, as shown in dashed lines62 in Fig. 2 will then cause end 45 of lifting pawl 43 to slide upwardlyalong the lower surface of tooth and eventually snap into and engagetooth 5 so that at the conclusion of the upward movement of actuatinglever 34, the lifting and holding pawls 43 and 46 are in the sameposition as shown in Fig. 1, being respectively in engagement with teeth5 and 13, however. It is thus seen that each oscillation of actuatinglever 34 between first and second intermediate positions as shown inFigs. 1 and 2 is accompanied by raising of the housing member 23 onetooth.

In order to provide for automatic reversing of my jack mechanism fromraising to lowering operation, I provide a latching member 63 positionedbetween healing plates 31 and 32 with its end 64 pivotally connectedthereto by a pivot pin 65 having its ends seated in holes 66 in the sidewall 25 and bearing plate 31, and side wall 26 and bearing plate 32, asbest seen in Fig. 7. Latching member 63 extends outwardly betweenbearing plates 31 and 32 away from teeth 22 of rack bar 21 and has anotch 67 provided in its lower side for at times engaging end 68 ofholding pawl 46, as will be hereinafter more fully described. Outer end69 of latching member 63 is also adapted at times to engage the upperend 71 of lifting pawl 43, as will be hereinafter described. Latchingmember 63 is urged toward the upper ends 68 and 71 of holding andlifting pawls 46 and 43 by means of a suitable coil spring 72 arrangedbetween the upper side of latching member 63 and the lower side of topwall portion 27, as shown.

I have further provided an elongated cam member 73 having one end 74secured to side wall 26 outwardly from hearing plate 32 and having itsother end 75 extending in spaced parallel relationship from the innersurface of side wall 26. It will further be observed that the free end75 of the cam member 73, which is rod-like in shape, is inclinedoutwardly and upwardly away from the outer edge of the bearing plate 32.A cam follower pin 76 is secured to the upper end 71 of lifting pawl 43extending toward the inner surface of side wall 26 and cooperating withthe cam member 73, as will now be described.

Referring now to Figs. 3, 4, and 5, in order to convert from lifting tolowering operation, actuating lever 34 is moved upwardly from its normalposition, as shown in dashed lines 77 in Fig. 3 to its extreme upperposition, as shown in solid lines in Fig. 3. This upward movement of theactuating lever 34 from its normal to its extreme upward position isaccompanied by upward movement of the lifting pawl 43. Close to the endof the upward stroke of actuating lever 34, the cam follower pin 76engages the lower surface of free end 75 of cam member 73 and passesupwardly over the end to engage the upper surface thereof, i.e., fromthe position shown in dashed lines 78 to that shown in solid lines inFig. 3. This motion is accompanied by raising of the lower end 45 of thepawl 43 along the underside of tooth 5 from the position shown in dashedlines 79 to that shown in solid lines in Fig. 3. It will be observed,however, that during this operation, lower end 49 of holding pawl 46 isstill in engagement with tooth 12 thus retaining housing member 23 inits normal position. It will also be observed that the upper end 71 oflifting pawl 43 has engaged end 69 of latching member 63 and raised thesame thus com pressing coil spring 72, however, at this point, thisaction is only incidental.

Referring now specifically to Fig. 4, lowering of the actuating lever 34from its extreme upward position, as shown in dashed lines 31 in Fig. 4in the direction shown by the arrow 82 causes the cam follower pin 76 tomove along the upper surface of free end 75 of cam follower member 73thus pivoting lifting pawl 43 about its pivot pin 44 thereby moving itslower end 45 from the position of Fig. 3, shown in dashed lines 83 inFig. 4 to a position away from teeth 22 as shown in solid lines in Fig.4. Continued downward movement of actuating lever 34 in the direction 82causes the cam follower pin 76 on upper end 71 of lifting pawl 43 topass over the end 74 of cam member 73 to the position shown in dashedlines 84 in Fig. 4. With the upper end 71 of the lifting pawl 43 thus nolonger restrained by cooperative engagement of cam follower pin 76 withfree end 75 of cam member 73, lower end 45 will now, under the influenceof coil spring 51, snap into engagement with the underside of tooth 4and continued downward movement of actuating lever 34 in the direction82 will result in lower end 45 of lifting pawl 43 being firmly engagedwith the next lower tooth 3, as shown in dashed lines 85 in Fig. 4. Itwill now be seen that as a result of moving actuating lever upwardly toits extreme upward position and thereafter lowering the same, liftingpawl 43 will be disengaged from tooth 4 and reengaged with tooth 3,lower end 49 of holding pawl 46, however, at this point still remainingin engagement with tooth 12.

Referring now particularly to Fig. 5, continued downward movement ofactuating lever 34 in the direction 82 to its extreme lower position asshown in solid lines in Fig. 5, causes the lifting pawl 43 to movehousing 23 upwardly in the direction shown by the arrow 86 from theposition shown in the dashed lines 87 in Fig. 5 to the position shown insolid lines. This upward movement of housing 23 causes the upper end 71of lifting pawl 43 to engage surface 88 of holding pawl 46 intermediateits end 68 and its pivot 47 thus camming holding pawl 46 about pivot pin47 so that its end 68 snaps into engagement with notch 67 of latchingmember 63, latching member 63 being urged downwardly by coil spring 72so that end 68 of holding pawl 46 is retained in notch 67 under theinfluence of coil spring 51. It will now be observed that the lower end49 of holding pawl 46 has been moved upwardly away from tooth 12,however, the lower end 45 of lifting pawl 43 is still firmly inengagement with tooth 3.

Upward movement of actuating lever 34 in the direc tion shown by arrow89 away from its extreme lower position shown in solid lines to itsposition shown in dashed lines 93 in Fig. 5 results in again loweringhousing 23 to a lower position shown in dashed lines 90. The initialdownward movement of housing 23 and simultaneous upward movement oflifting pawl 43 responsive to upward movement of actuating lever 44results in upper .end 71 of lifting pawl 43 moving into engagement withthe underside of end 69 of latching member 63, as shown in dashed lines91 in Fig. 5 when the housing 23 has lowered to about the position shownin dashed lines 87. Further downward movement of housing 23 andsimultaneous upward movement of lifting pawl 43 results in lifting pawl43 pivoting latching member 63 upwardly about pivot pin 65 against coilspring 72 until latching member 63 assumes nearly the position shown inFig. 3 when housing 23 is lowered to the position shown in dashed lines90. This upward pivoting of latching morn .ber 63 results indisengagement of notch 67 from upper lever 34 in the position shown indashed lines 93 in Fig. 5

with the lower ends 45 and 49 of lifting and holding pawls 43 and 46 inengagement with teeth 3 and 11 and with .the upper end 71 of liftingpawl 43 in engagement with end 69 of latching member 63 is exactly thesame as the position of the mechanism shown in Fig. 1, with, however,the lower ends of the pawls respectively engaging one lower tooth, i.e.,3 and 11. Still further, upward movement of actuating lever 34 to theposition shown in solid lines in Fig. 3 results in pin 76 again engagingthe lower surface of end 75 of cam 73, as shown in Fig. 3, thereby toinitiate the next lowering cycle. It is thus seen that by virtue of onecomplete oscillation of operating lever 34 between its upper and lowerextreme positions the housing member 23 is lowered by one tooth.

T It will now be readily seen that raising or lifting action of myimproved jack construction is accomplished by oscillatory motion of theactuating lever 34 between intermediate positions, i.e., short strokesof the jack handle 42, and that conversion to lowering action isaccomplished merely by changing from the short intermediate strokes tolong full strokes, thus oscillating the actuating lever 34 between itsextreme upper and lower positions. Conversion fromlowering to liftingaction is accomplished in the same manner, i.e., by merely convertingfrom long full strokes to short intermediate strokes of jack handleWhile I have illustrated a jack construction in which the rack bar 21 isstationary with the housing and operating mechanism assembly being movedupwardly and downwardly with respect to the bar, it will be readilyapparent that the mechanism can readily be inverted with the housinghaving a base secured thereto and with the rack bar 21 being movedupwardly and downwardly by the operating mechanism; in this case, theupper end of the rack bar 21 will have a suitable pad secured thereto,as is well known in the art. Also, while my invention has beenillustrated as specifically embodied in a vehicular-type jack, it willbe readily comprehended that it is equally advantageously employed inother types of jacks.

It will now be seen that I have provided a simple automaticallyreversible jack construction incorporating only three major operatingcomponents, i.e., the lifting and hold pawls and the latching member,two springs, and the cooperating cam member and cam follower pin. It isthus seen that my jack construction is readily assembled and thus lendsitself to quantity production.

While I have illustrated and described a specific embodiment of myinvention, further modifications and improvements Will occur to thoseskilled in the art and I desire, therefore, in the appended claims tocover all modifications which do not depart from the spirit and scope ofthis invention.

What is claimed is: a

1. An automatic reversing jack comprising: an elongated toothed rack'bar; a housing having a portion embracing said bar and relativelyslidable thereon; an actuating lever pivotally mounted on said housingfor manual oscillation between first and second extreme positionsthrough first and second intermediate positions; a holding pawlpivotally mounted on said housing and having an end adapted to engagethe teeth of said bar; a lifting pawl pivotally mounted on said leverand having an end adapted to engage said teeth; spring means urging saidpawls into engagement with said teeth whereby oscillation of said leverbetween said first and second intermediate positions alternately causesone pawl to engage a tooth and the other pawl to slide over one toothand to engage the next tooth thereby moving said housing in onedirection with respect to said bar; a latching member pivotally mountedon said housing and having a portion adapted at times to engage saidholding pawl thereby to hold the same out of engagement with said teeth;and means cooperating with said lifting pawl for causing the same tomove out of engagement with one tooth and into engagement with anothertooth responsive to movement of said lever into and away from one ofsaid extreme positions; said lifting pawl being adapted to move saidholding pawl into engagement with said latching member responsive tomovement of said lever to the other of said extreme positions; saidlifting pawl being further adapted to move said latching member out ofengagement with said holding pawl responsive to movement of said leveraway from said other extreme position whereby oscillation of said leverbetween said extreme positions moves said housing in the oppositedirection with respect to said bar.

2. An automatic reversing jack comprising: an elongated toothed rackbar; a housing having a portion embracing said bar and relativelyslidable thereon;- an actuating lever pivotally mounted on said housingfor manual oscillation between first and second extreme positionsthrough first and second intermediate positions; a holding pawlpivotally mounted on said housing and having an end adapted to engagethe teeth of said bar; a lifting pawl pivotally mounted on said leverand having an end adapted to engage said teeth; spring means urging saidpawls into engagement with said teeth whereby oscillation of said leverbetween said first and second intermediate positions alternately causesone pawl to engage a tooth and the other pawl to slide over one toothand to engage the next tooth thereby moving said housing in onedirection with respect to said bar; a latching member pivotally mountedon said housing and having a portion adapted at times to engage saidholding pawl thereby to hold the same out of engagement with said teeth;:a cam member on said housing; and a cam follower member on said liftingpawl cooperatively engageable with said cam member responsive tomovement of said lever to one of said extreme positions, said camfollower member cooperatively engaging said cam member during movementof said lever away from said one extreme position thereby causing saidone end of said lifting pawl to move out of engagement with one toothand to reengage an adjacent tooth; said lifting pawl being adapted tomove said holding pawl into engagement with said latching memberresponsive to movement of said lever to the other of said extremepositions; said lifting pawl being further adapted to move said latchingmember out of engagement with said holding pawl responsive to movementof said lever away from said other extreme position whereby oscillationof said lever between said extreme positions moves said housing in theopposite direction with respect to said bar.

3. An automatic reversing jack comprising; an elongated toothed rackbar; a housing having a portion embracing said bar and relativelyslidable thereon; an actuating lever pivotally mounted on said housingfor manual oscillation between first and second extreme positionsthrough first and second intermediate positions; a holding pawlpivotally mounted on said housing and having adapted to engage saidteeth; spring means urging said pawls into engagement with said teethwhereby oscillation of said lever between said first and second intermediate positions alternately causes one pawl to engage a tooth and theother pawl to slide over one tooth and to engage the next tooth therebymoving said housing in one direction with respect to said bar; alatching member pivotally mounted on said housing and having a portionadapted at times to engage said holding pawl thereby to hold the sameout of engagement with said teeth; an elongated rod-like cam memberhaving one end secured to said housing and its other end extending inspaced parallel relationship therewith; and a cam follower pin extendingoutwardly from said lifting pawl, said pin ini tially engaging one sideof said other end of said cam member and moving thereover onto the otherside thereof responsive to movement of said lever to one of said extremepositions, said pin initially following said other side of said otherend of said cam member and thereafter disengaging the same responsive tomovement of said lever away from said one extreme position therebycausing said one end of said lifting pawl to move out of engagement withone tooth and to reengage an adjacent tooth; said lifting pawl beingadapted to move said holding pawl into engagement with said latchingmember responsive to movement of said lever to the other of said extremepositions; said lifting pawl being further adapted to move said latchingmember out of engagement with said holding pawl responsive to movementof said lever away from said other extreme position whereby oscillationof said lever between said extreme positions moves said housing in theopposite direction with respect to said bar.

4. An automatic reversing jack comprising: an elongated toothed rackbar; a housing having a portion embracing said bar and relativelyslidable thereon; an actuating lever having one end pivotally connectedto said housing and having its other end extending out of said housingand adapted to be manually oscillated between first and second extremepositions through first and secd and intermediate positions; a liftingpawl pivotally connected intermediate its ends to said lever at a pointeccentric with respect to the connection of said lever to said housing,said lifting pawl having one end adapted to engage the teeth of saidbar; a holding pawl pivotally connected intermediate its ends to saidhousing and having one end adapted to engage said teeth; spring meansurging said pawls into engagement with said teeth whereby oscillation ofsaid lever between said first and second intermediate positionsalternately causes one pawl to engage a tooth and the other pawl toslide over one tooth and to engage the next tooth thereby moving saidhousing in one direction with respect to said bar; a latching memberhaving one end pivotally connected to said housing and having a portionadapted at'times to engage the other end of said holding pawl thereby tohold said one end thereof out of engagement with said teeth; a cammember on said housing; a cam follower'member on the other end of saidlifting pawl cooperatively engageable with said cam member responsive tomovement of said lever to said first extreme position, said cam followermember cooperatively engaging said cam memher during movement of saidlever away from said first extreme position thereby causing said one endof said lifting pawl to move out of engagement with one tooth and toreengage an adjacent tooth; said other end of said lifting pawl beingadapted to engage said holding pawl and to move the same so that theother end thereof engages said latching member portion responsive tomovement of said lever to the second extreme position; said other end ofsaid lifting pawl being further adapted to engage the other end of saidlatching member and to move the same out of engagement with the otherend of said holding pawl responsive to movement of said lever away fromsaid other extreme position whereby oscillation of said lever betweensaid extreme positions moves said housing in the opposite direction withrespect to said bar.

References Cited in the file of this patent UNITED STATES PATENTS

